Ensuring Tokyo Bay is fit for swimming ahead of the 2020 Olympics

If you squint your eyes, it almost looks like Club Med: an expanse of blue sea, a stretch of beach, white tents and umbrellas on the sand, and plenty of staff ready to help out. However, this isn’t a tropical paradise, it’s Tokyo Bay and Odaiba Plage is an attempt to turn it into a swimming spot.

Taking the plunge

From July 31 to Aug. 5, the small beach at Odaiba, the artificial island off downtown Tokyo, was open for bathing. Normally, swimming isn’t allowed at Odaiba Plage due to water quality concerns, but rebranding can work wonders. Odaiba Plage, its temporary moniker, was inspired by Paris Plages, a series of summer leisure spots that have been organized along the Seine and other Paris waterways since 2002.

Odaiba Plage was one of the more unusual swimming experiences I’ve had in Japan. It was organized to the point of being slightly Kafkaesque. There were around seven swimmers and three times that number of staff, including lifeguards on the beach and in the water on surfboards. I was directed to a reception desk and asked to sign a document titled “Odaiba Plage Swimming Agreement.” It was a contract listing 23 rules and clauses to observe, including injunctions against displaying tattoos, using audio systems and causing inconvenience to other guests, and releasing sponsor Minato Ward of all liability. Rule No. 9 said, “When the yellow flag is out in the venue, please refrain from swimming with your face inside the water,” adding that the “bathing forecast” was based on collaborative research with the University of Tokyo.

Odaiba Plage is an attempt to turn Tokyo Bay into a swimming spot. | TIM HORNYAK

Having signed, I was given a wristband with a number on it and shown to a changing tent with lockers. On the way was a chalkboard displaying information about weather and water quality conditions: It was OK to put my face in the water. I could finally take a dip in the Pacific Ocean.

With the ambient temperature at 35.8 degrees Celsius, the waters of Tokyo Bay felt cool and refreshing at 31 degrees. In the distance was the green slab of Daiba Park, one of the batteries built to fend off American incursions into Japan in the 19th century, and beyond that the towers of Rainbow Bridge, along with gantry cranes at the Port of Tokyo. Airplanes on approach to Haneda buzzed overhead, cormorants flew by and goby fish jumped out of the sea. It was an odd, almost idyllic scene.

“They say the water quality is fine, so it’s good to cool off here,” said a Minato Ward resident who had come to the beach with her husband and two children.

A few dozen meters from the shore, however, was a fine-mesh orange plastic barrier surrounding the swimming area. It was set up to make the swimming area safe from contaminants and other undesirables.

“The barriers help keep out dangerous fish like stingrays,” said one lifeguard. “The water is OK here, but you wouldn’t want to drink it.”

Odaiba Plage features an underwater barrier that is designed to keep bacteria and stingrays out. | TIM HORNYAK

Bayside bacteria blues

Odaiba Plage is a bid to show that Tokyo Bay is at least partly safe to swim in because it’s one of the venues for the Tokyo 2020 Olympic and Paralympic Games. Odaiba Marine Park will host part of the triathlon and marathon swimming events for the games, but the waters are anything but pristine.

In October 2017, organizers said the water had high levels of E. coli and other fecal coliform bacteria — as much as 20 times the accepted limit for the former and seven times for the latter. E. coli is found in the environment, food and the intestines of people and animals; some strains can cause diarrhea or serious illness. The presence of E. coli and other coliform bacteria in water is “a strong indication of recent sewage or animal waste contamination,” according to the U.S. Environmental Protection Agency.

The revelation was based on tests conducted over 26 days between July and September last year. Water quality standards set by the International Swimming Federation for marathon swimming were met on only 10 days, while standards set by the International Triathlon Union for triathlon were met on only six days.

Water quality at Odaiba can vary with heavy rain, when the sewerage system can’t cope with the overflows. August 2017 had three straight weeks of daily precipitation, the second-longest spell for the month since observations began, and the 2017 survey results have fanned concerns about the safety of the Olympic venue. In March, the Japanese Swimming Federation moved the open water venue for the 2018 Pan Pacific Championships, a quadrennial swimming event, from Odaiba Marine Park to Hojo Beach in Tateyama, Chiba Prefecture, 70 kilometers to the south.

“As the Olympics approach, it will likely cause anxiety among international athletes,” sports columnist Kenji Fujiyama wrote in the Sports Nippon daily. “Overseas reactions to environmental problems can be on a scale that in Japan is unthinkably large. In order not to cause unnecessary uneasiness, we need a detailed explanation by experts.”

Volunteers place bamboo in Tokyo Bay to help foster an environment for marine life. | COURTESY OF YUZO SEKIGUCHI

Wanted: A Mario Brothers army

Around 120 rivers flow through Tokyo, including major arteries such as the Tama and Sumida. These empty into Tokyo Bay, which at one time was one of the most polluted coastal areas in Japan.

In the age of breakneck economic growth after World War II, waterways in the capital were sometimes choked with trash and foam generated by pollution. Contaminated water from paper mills on the Edo River damaged fisheries in the bay.

In May and June of 1958, dozens of fishermen outraged over massive numbers of dead fish stormed the Honshu Paper mill to demand redress. Riot police were summoned and nearly 150 people were injured in a melee, but the incident helped pave the way for central government laws to protect the quality of public waters and to regulate industrial effluent. However, poor oxygenation, organic pollutants and excess nutrients from surface runoff, a phenomenon known as eutrophication, remain stubborn problems for water quality in the bay, according to Midori Kawabe, a researcher at Tokyo University of Marine Science and Technology.

“Although it hasn’t returned to the way it was in the 1950s, it’s thought that the water quality of Tokyo Bay is improving when compared to before,” says Hiroaki Furumai, a professor at the Research Center for Water Environment Technology at the University of Tokyo’s School of Engineering. “Pollution that has accumulated in the bottom mud for many years is the reason for the oxygen-poor water, leading to blue tides in summer and eutrophication.”

While industrial pollution has been curbed, the design of Tokyo’s sewer system remains a problem for water in the bay. Even after Japan began modernizing in the 19th century, a lack of clean drinking water and use of night soil as fertilizer was fueling disease outbreaks such as cholera, which killed more than 530,000 people between 1877 and 1900, according to William Johnson, a professor of East Asian studies at Wesleyan University.

Another threat was flooding from typhoons. To get rid of sewage water and surface runoff as quickly as possible, Tokyo began installing combined sewerage systems in 1908. These traditional systems, used in more than 190 cities in Japan as well as major metropplitan areas such as New York and London, are relatively easy to build because they need only one main pipe. However, they also mix storm runoff with raw or partially treated sewage and send the excess into bodies of water in times of heavy precipitation, contaminating them.

Children swim in the ocean at Odaiba Beach in July 2014. | KYODO

Under a 1965 legal revision, sewer operators had to protect water quality in open waters such as Tokyo Bay. Tokyo’s Bureau of Sewerage only managed to cover 100 percent of the 23 wards with sewer pipes in 1995, and it’s continuing to build out the network.

“We’re working to increase the capacity of sewer pipes so they can send more sewage to water reclamation centers, and to improve facilities that store particularly dirty sewage in the initial stages of rainfall,” says Masayuki Ito, a spokesperson with the bureau, when asked about the problem of sewer bacteria in the bay.

Today, the bureau runs 20 plants that treat approximately 5.45 million cubic meters of sewage daily. More than 80 percent of the sewers in Tokyo’s 23 central wards, including all the wards on Tokyo Bay, are combined sewerage systems, with the rest on separate systems for precipitation and sewage.

“In sunny weather, the water quality of Odaiba is very good, mainly because household wastewater is properly treated,” says Yutaka Kameda, an associate professor of engineering at Chiba Institute of Technology. “But when it rains, the large volume of wastewater is too much for treatment plants, so wastewater containing some rainwater will be directly discharged to rivers without any treatment.”

Tokyo has tried measures such as pumps and reservoirs to deal with downpours, but completely overhauling such a large legacy system — there are about 16,000 kilometers of sewer pipes in the 23 central wards — would be a massive undertaking.

“When you have a combined sewer system and a heavy downpour, to protect the city from flooding, we have no choice but to discharge sewer and rainwater into rivers and the sea,” says Kouichi Yajima, a manager in the Metropolitan Government’s Olympic and Paralympic Games Preparation Office. “In addition, it’s thought that inflows from other prefectures lacking sewer system coverage is one of the reasons for the deterioration of water quality at Odaiba Marine Park.”

In the swim of things

In the 1960s, all swimming beaches in the capital were closed due to pollution. In 2003, when swimming and even wading at Odaiba was prohibited, a headline from The Japan Times was unflinching: “Odaiba beach not even safe for sewer rats to dip in.” Odaiba, however, has held limited swims for the past five years, with this year’s six-day run under the new Odaiba Plage brand the longest ever.

Odaiba isn’t the only place to take a dip in bayside Tokyo. In 2012, a nonprofit organization named Furusato Tokyo wo Kangaeru, a grass-roots movement to reclaim the bay, began trial swims at Kasai Rinkai Park in Edogawa Ward; the program expanded quickly in the following years. In 2015, the Tokyo government backed the movement and officially opened the beach. Every July on Marine Day, the NPO holds a prayer ceremony with a Shinto priest and opens the beach to swimmers.

For Yuzo Sekiguchi, the organization’s 70-year-old president, it has been a long road to get swimming beaches back. He recalls his elementary school days when he would swim off Edogawa, fish for sea bass and gather seaweed. Aiming to reclaim Tokyo Bay as a resource and leisure spot for the community, he and other activists took inspiration from the rehabilitation of Chesapeake Bay in the U.S. and began experimenting with oysters as natural cleaning agents. Oysters can purify 400 liters of water per day, and when enough were put into the bay, the results began showing in water quality tests. To provide a growth environment for oysters and other marine organisms, the NPO has planted more than 1,000 bamboo shoots along the shore. Japanese sea bass, flathead grey mullet and Japanese river goby are among the species that have been populating the area.

The group now organizes lifeguards, trash cleanups and activities for children including bamboo planting and how to cast traditional fishing nets. While wastewater after heavy rain — as well as red stingrays that might get through protective barriers — can still be a threat, the project has met with success. The 2018 swim season at the park lasted 42 days through Aug. 26, a week longer than the year before, and 45,000 people went for a swim.

“I think it’s important that local people have a stake in the marine environment and make it part of their sense of hometown,” says Sekiguchi, who published a book on the subject this year. “We want to have an environment in which parents can enjoy the seaside with their children and they don’t have to go to Hawaii for a beach experience. To make it sustainable, we have to foster a community culture and not rely on events only.”

Participants take part in a swimming event to promote the Tokyo 2020 Olympics at Odaiba Beach in August 2013. | KYODO

As for the organizers of the 2020 Olympics, they’re still pushing Odaiba as an ideal venue for some of the water events. A new report on the effectiveness of the underwater barrier is expected to be released in the next few weeks.

“Over the past 20 years, Odaiba Marine Park has been the venue for the Japan Triathlon National Championships and more than 2,000 athletes have participated,” says Koji Murofushi, a former Olympic athlete in hammer throw and now director of sports for the games. “But as the quality of water is greatly affected by the weather and other factors, Tokyo and the Organizing Committee, based on standards set by international sports federations, are considering future countermeasures for a smooth competition.”

Odaiba Plage may continue well into the future as part of the legacy of the games, but Tokyo Bay, at least along the shores of the world’s most populous metropolitan area, will likely never be a place for mass frolicking in the waves.

“Some politicians want to have a beach that can be opened to the general public after the Olympic Games,” Kameda says. “But with the current water quality, that would be difficult for ordinary citizens, children and elderly people who are not tough like triathletes. It’s assumed that inflammation rates would be very high.”